Flame tubes

ABSTRACT

A flame tube for a gas turbine engine comprises a tubular element having an inlet and an outlet at opposite ends thereof. A frusto-conical baffle is mounted at the inlet of the tube element so as to direct air entering the inlet against the wall of the tube element. A plurality of vanes are secured to the baffle and to the tube element so as to locate the latter with respect to the baffle. The vanes, are mounted by means of a plate and a bush on a chamber within which the flame tube is mounted. The bush receives a fuel atomizer for injecting fuel into the tube element through an axial opening in the baffle and the air which passes into the tube element via the axial opening has a swirl imparted thereto by the vanes.

United States Patent [191 Sedgwick Oct. 23, 1973 41 FLAME'TUBES [75]Inventor:' Gordon Sedgwick, Nelson, England [73] Assignee: LucasAerospace Limited, Birmingham, England [22] Filed: July 28, 1972 21Appl. No.: 276,159

[30] Foreign Application Priority Data Aug. 10, 1971 Great Britain37,447/71 [5 6] References Cited UNITED STATES PATENTS v FOREIGN PATENTSOR APPLICATIONS 869,446 3/1953 Germany 239/403 839,267 6/1960 GreatBritain.... 239/405 277,101 8/1930 ltaly 239/403 PrimaryExaminerRobertS. Ward, Jr. Attorney-John C. Holman et al.

[57] ABSTRACT A flame tube for a gas turbine engine comprises a tubularelement having an inlet and an outlet at opposite ends thereof. Afrusto-conical baffle is mounted at the inlet of the tube element so asto direct air enteringthe inlet against the wall of the tube element. Aplurality of vanes are secured to the baffle and to the tube element soas to locate the latter with respect to the baffle. The vanes, aremounted by means of a plate and a bush on a chamber within which theflame tube is mounted. The bush receives a fuel atomizer forinjectingfuelinto the tube element through an axial opening in thebaffle and the air which passes into the 1,788,495 1 1931 Sh d.... 39 3I 1991894 2 5 532;: 2 3: tube element via the axial opening has a SWll'l1m- 2,210,428 8/1940 I P655311] 235/39 x parted thereto by the vanes-2,366,605 1/ 1945 Evans 239/430 X 6 Claims, 2 Drawing Figures 2,414,4421/1947 Breault 239/430 X 3,700,173 10/1972 Ketchum ..239/405 X l l I I 1I I II II 1 FLAME TUBES BACKGROUND OF THE INVENTION This inventionrelates to flame tubes for gas turbine engines, and has an an object toprovide a flame tube in a convenient form.

SUMMARY OF THE INVENTION According to the invention, a flametube for agas turbine engine comprises a tube element provided at opposite endswith an inlet and an outlet, a baffle within the tube element adjacentthe inlet and adapted to direct air entering the inlet against the tubeelement wall, said baffle having a through-passage therein, a pluralityof vanes secured to the baffle and .the tube element to locate thelatter with respect to the baffle, said vanes being arranged to impart aswirling motion to air directed through said through-passage andmounting means secured to said vanes, said mounting means being adaptedto receive a fuel atomizing device and to engage a structure upon whichthe flame tube, is in use, located, said atomizing device injecting fuelinto the tube element via said through-passage.

An example of a flame tube according to the invention will now bedescribed with reference to the accompanying drawings in which:

BRIEF DESCRIPTION OF THE DRAWINGS 1 FIG. 1 is a section through a flametube, and FIG. 2 is a section on line 2-2 in FIG. 1.

DETAILED DESCRIPTION OF THE INVENTION The flame tube has a tube elementprovided with an inlet 11 and'an outlet 12. Within the inlet end ofelement 10 is a baffle 13 of generally frusto-conical form and having anaxial through-passage l4. Secured to the upstream side of baffle 13 is areinforcing ring 23. Secured to ring 23 are a plurality of vanes 15,which are also secured to the tube element 10. As seen in FIG. 2 attheir inner ends 15b vanes 15 are tangential to an imaginary circlewhich is of somewhat greater diameter than the passage 14. Each vane 15has an outer portion 15b which extends radially with respect to the axisof the passage 14. A further portion 150 of each vane 15 extends fromthe portion 15b to lie against the wall of element 10. A reinforcingportion 15d extends from the portion 15c to lie against and reinforcethe portion 15b of an adjacent vane 15, to reinforce the radial portionsof the next adjacent vanes. Secured to the portions 150 of the vanes isa mounting comprising a circular plate 16 and a bush 17 secured to theplate 16 and axially aligned with the tube element 10.

The bush 17 is adapted to receive a fuel atomizer shown generally at 18.Bush 17 is externally threaded to receive a nut 19 by means of which themounting is secured to an end plate 20 of a chamber within which theflame tube is mounted. The plate 16 abuts the end plate 20 whereby anyload on the tube element 10 is transferred via the vanes 15 to the endplate 20.

The tube element 10 has slots 21 through its wall intermediate the inlet11 and outlet 12. Holes 22 also extend through the wall of element 10downstream of slots 21.

In use, fuel is supplied to the flame tube via fuel atomizer l8 and airunder pressure is supplied to the chamber surrounding the flame tube.Air enters the flame tube via passage 14 and is also directed againstthe wall of element 10 by the baffle 13. The portions 15a of vanes 15impart a swirling motion to the air passing into the tube element 10through the axial passage 14 internally of the baffle 13. Secondarycombustion air and dilution air enter the flame tube via slots 21 andholes 22 respectively. I

I claim:

1. A flame tube for a gas turbine engine, comprising a tube elementprovided at opposite ends with an inlet and an outlet, a baffle withinthe tube element adjacent the inlet and adapted to direct air enteringthe inlet against the tube element wall, said baffle having athrough-passage therein, a plurality of vanes secured to the baffle andthe tube element to locate the latter with respect to the baffle, saidvanes being arranged to impart a swirling motion to air directed,through said through-passage and mounting means secured to said vanes,said mounting means receiving a fuel atomizing device and engaging astructure upon which the flame tube, is in use, located, said atomizingdevice injecting fuel into the tube element via said through-passage.

2. The flame tube as claimed in claim I, wherein each vane has a portionwhich extends so as to lie against an outer portion of an adjacent vanethereby to reinforce that outer portion.

3. The flame tube as claimed in claim 1, wherein each vane has a portionwhich lies against the tube element wall.

4. The flame tube as claimed in claim 1, wherein the mounting meanscomprises a plate secured to an inner portion of each vane and a bushsecured to the plate and adapted to be detachably secured to thestructure and to receive the fuel atomizing device.

5. The flame tube as claimed inclaim 4, wherein the bush is externallyscrew-threaded to engage a nut rigidly connected with said structure.

6. The flame tube as claimed in claim 1, wherein each vane has an innerend portion tangential to an imaginary circle of somewhat greaterdiameter than the through-passage, with said inner end portionsimparting the swirling motion to the air directed through thethrough-passage.

1. A flame tube for a gas turbine engine, comprising a tube elementprovided at opposite ends with an inlet and an outlet, a baffle withinthe tube element adjacent the inlet and adapted to direct air enteringthe inlet against the tube element wall, said baffle having athrough-passage therein, a plurality of vanes secured to the baffle andthe tube element to locate the latter with respect to the baffle, saidvanes being arranged to impart a swirling motion to air directed,through said through-passage and mounting means secured to said vanes,said mounting means receiving a fuel atomizing device and engaging astructure upon which the flame tube, is in use, located, said atomizingdevice injecting fuel into the tube element via said through-passage. 2.The flame tube as claimed in claim 1, wherein each vane has a portionwhich extends so as to lie against an outer portion of an adjacent vanethereby to reinforce that outer portion.
 3. The flame tube as claimed inclaim 1, wherein each vane has a portion which lies against the tubeelement wall.
 4. The flame tube as claimed in claim 1, wherein themounting means comprises a plate secured to an inner portion of eachvane and a bush secured to the plate and adapted to be detachablysecured to the structure and to receive the fuel atomizing device. 5.The flame tube as claimed in claim 4, wherein the bush is externallyscrew-threaded to engage a nut rigidly connected with said structure. 6.The flame tube as claimed in claim 1, wherein each vane has an inner endportion tangential to an imaginary circle of somewhat greater diameterthan the through-passage, with said inner end portions imparting theswirling motion to the air directed through the through-passage.